Gary Hooper, Thomas Rogne and James Forrest remain missing for Saturday's Clydesdale Bank Premier League clash at Aberdeen but Lennon is hopeful they will make the flight to Portugal on Monday.

Lennon also hopes to have Scott Brown fit as his skipper fights an ongoing hip problem while fellow midfielder Joe Ledley is looking to shake off a knock he picked up in last weekend's draw with St Johnstone.

Speaking about the Pittodrie clash, Lennon said: "Gary won't make it. We are hoping he will start training on Sunday.

"Lassad is back in the squad. Rogne will hopefully train on Sunday.

"Forrest, at first we thought it was a hamstring strain, but it looks like he has damaged a nerve. We are hoping that will settle down and he can travel with us on Monday.

"Brown and Ledley are doubts for Saturday but they should make Tuesday."

Hooper has been missing with a hamstring problem while Rogne has a calf injury. Left-back Emilio Izaguirre is out for about another month with a hamstring strain.

Lennon has clear memories of the Aberdeen glory days - some fond and some painful - and is relishing a top-of-the-table clash at Pittodrie.

Lennon's team travel to the Granite City one point above Craig Brown's men, who have only lost once in the Clydesdale Bank Premier League since their late 1-0 defeat at Parkhead on the opening day.

The televised midday game has captured the imagination in the north east of Scotland with Aberdeen having the chance to leapfrog Celtic and leaders Hibernian and go top of the SPL, even if it might only be for a matter of hours.

Lennon grew up in an era when Alex Ferguson's Aberdeen dominated Scottish football.

"Obviously I remember that great Aberdeen team, and the highlight was the Cup Winners' Cup final against Real Madrid," the former Northern Ireland international said.

"I remember sitting in the house as a boy watching it and jumping up and down because it was a Scottish team that were doing it.

"They had a great manager who has gone on to unbelievable things in his career. Gordon Strachan, Mark McGhee, Eric Black, Alex McLeish, Willie Miller, Jim Leighton, I can rhyme the team off near enough.

"They were an exceptional team in exceptional times. I remember going to a (Scottish Cup) semi-final I think in '83, Celtic-Aberdeen, and Aberdeen won 1-0.

"I was only a boy and it was one of the first Celtic games I went to see."

After the collapse of Rangers, Celtic were generally expected to surge well ahead in the title race but they have faced a challenge at home from Aberdeen and Hibs, teams who have struggled in recent years, while exceeding expectations in the Champions League.

"I think it's very healthy for Aberdeen," Lennon said. "I'm sure there will be a really good crowd. They have recruited well in the summer.

"Craig's very shrewd and obviously with Archie [Knox, Brown's assistant] there they have great experience in the background. And they have been pretty consistent this season, which is something you can't throw at Aberdeen over the last few seasons.

"It will be a good atmosphere, you'll have two big clubs in Scotland going at it and we'll not be thinking about Benfica until two o'clock on Saturday afternoon.

"It's an important game for us. Our league form recently hasn't been great. It's not a major concern for me but it's a game where we can set a marker down."

Lennon had prepared a response to those criticising his side's SPL form, which has seen them pick up two points from three games and often struggle around the European fixtures.

"There are people casting aspersions and saying we are being complacent because there is no Rangers," he said.

"For some players Saturday will be the 30th game of the season already in competitive games and internationals.

"We are two points behind with a game in hand. There are a lot of other clubs who aren't top of their respective leagues so we are there or thereabouts so that's why I don't think there should be too much negativity being thrown at us.